A synthetic biology tool for contact-dependent synthetic cell communication

Cell-cell communication and signal transduction through direct cell-cell contact are found ubiquitously in biology, with examples including T-cell activation upon contact formation with antigen-presenting cell in immunological synapses and electrical signal transduction in neuronal synapses. Despite the prevalence of intercellular communication at cell-cell interfaces, it is difficult to engineer and reconstitute functional proteins at membrane-membrane interfaces. A synthetic biology tool that can recapitulate signal transduction exclusively at membrane-membrane interfaces will be useful for designing synthetic intercellular communication pathways or providing a potential replacement for damaged and malfunctional natural cell-cell communication systems. Here, we present programmable activation of a split bioluminescent protein, NanoBiT, at the membrane-membrane interface between synthetic cells. We utilize a peptide-protein pair called SpyTag and SpyCatcher as adapter proteins to mediate functional reconstitution of NanoBiT. We illustrate an example of downstream protein activation through a designed light-based communication system by using a pair of photoactivatable proteins, iLID and SspB inside synthetic cells and demonstrate iLID-SspB dimerization triggered by reconstituted NanoBiT bioluminescence.